WO2016006484A1

WO2016006484A1 - Large-building inspection device

Info

Publication number: WO2016006484A1
Application number: PCT/JP2015/068599
Authority: WO
Inventors: 谷野貴広; 重田和樹
Original assignee: 東レ株式会社
Priority date: 2014-07-08
Filing date: 2015-06-29
Publication date: 2016-01-14
Also published as: JPWO2016006484A1; JP6662291B2

Abstract

The purpose of the present invention is to provide a large-building inspection device having a configuration optimized for detecting high-energy transmission X-ray. The present invention provides a large-building inspection device comprising an irradiation function of irradiating a large building with an X-ray from an X-ray source with an acceleration voltage of 500 kV to 30 MV and a detection function of detecting the X-ray transmitted through said large building using a radiation detector, wherein said radiation detector is provided with: a substrate; and a scintillator panel comprising barrier ribs placed on the substrate and a phosphor layer filled in cells partitioned by the barrier ribs.

Description

Inspection equipment for large structures

The present invention relates to an inspection apparatus for large structures.

In recent years, in high-speed structures such as highways that have been built for a long time, that is, large structures, deterioration of reliability due to aging has become a problem. Although the repair is an urgent task, it is necessary to grasp the internal structure and the like in advance. Therefore, the importance of a non-destructive inspection method that does not cause destruction of used concrete or the like is increasing.

Examples of non-destructive inspection methods include ultrasonic flaw detection and X-ray transmission tests. Among them, the X-ray transmission test irradiates a large structure made of concrete or the like with high-energy X-rays and transmits the large structure. This is a method of detecting a X-ray with a flat panel detector and obtaining a transmission image corresponding to the intensity of the transmission X-ray (Patent Document 1).

JP-A-10-197456

However, in the conventional indirect conversion type flat panel detector for medical or industrial inspection, the thickness of the phosphor layer for converting the transmitted X-rays into scintillation light is too thin, so that the absorption of high-energy transmitted X-rays is small and the sensitivity Was insufficient. On the other hand, when the sensitivity is improved by increasing the thickness of the phosphor layer, the scintillation light scattering in the phosphor layer becomes significant, and the transmitted image obtained on the contrary becomes unclear. It had been.

Therefore, an object of the present invention is to provide an inspection apparatus for a large structure having a configuration optimized for detecting high energy transmitted X-rays.

This object is achieved by any of the following technical means.
(1) An irradiation function for irradiating a large structure with an X-ray from an X-ray source having an acceleration voltage of 500 kV to 30 MV, and a detection function for detecting an X-ray transmitted through the large structure with a radiation detector; The radiation detector comprises a substrate, a partition wall placed on the substrate, and a phosphor layer filled in a cell partitioned by the partition wall. An inspection device for large structures provided with a scintillator panel.
(2) The inspection apparatus for large structures according to (1), wherein the reflectance of the substrate and the partition placed on the substrate is 25 to 85%.
(3) The scintillator panel has a reflective layer between the partition wall and the phosphor layer, and the reflective layer contains a metal oxide, and is a large size as described in (1) or (2) above. Structure inspection equipment.
(4) The inspection apparatus for large structures according to (3), wherein the average thickness of the reflective layer is 5 to 50 μm.
(5) The large structure according to (3) or (4), wherein the metal oxide is a compound selected from the group consisting of titanium oxide, zirconium oxide, aluminum oxide, barium oxide, bismuth oxide and gadolinium oxide. Inspection equipment.
(6) The average thickness of the reflective layer in the upper half of the cell is greater than the average thickness of the reflective layer in the lower half of the cell, according to any one of (3) to (5) above Inspection equipment for large structures.
(7) The large structure according to any one of (1) to (6), wherein the phosphor layer contains a granular phosphor, and the phosphor has an average primary particle diameter of 1 to 50 μm. Inspection equipment.
(8) The scintillator panel has a shielding layer between the partition wall and the phosphor layer, and the shielding layer is made of a metal, and is a large-size device according to any one of (1) to (7). Structure inspection equipment.
(9) The inspection apparatus for a large structure according to any one of (1) to (8), wherein a height of the partition wall is 0.4 mm or more.
(10) The inspection apparatus for a large structure according to any one of (1) to (9), wherein the phosphor layer has a plurality of modes having different compositions and / or thicknesses.
(11) When the X-ray absorption rate in the phosphor layer having the maximum X-ray absorption rate is P and the X-ray absorption rate in the phosphor layer having the minimum X-ray absorption rate is Q, P / Q ≧ The inspection apparatus for a large structure according to any one of (1) to (10), which satisfies a relationship of 1.5.

According to the present invention, it is possible to inspect the internal structure or the like of a large structure with high accuracy while being non-destructive.

It is sectional drawing which represented typically the structure of the radiation detector which the inspection apparatus of the large sized structure of this invention comprises. It is sectional drawing which represented typically the structure of the scintillator panel which the inspection apparatus of the large sized structure of this invention comprises. It is sectional drawing which represented typically the structure of the radiation detector which the inspection apparatus of the large sized structure of this invention comprises. It is the perspective view which represented typically the structure of the scintillator panel which the inspection apparatus of the large sized structure of this invention comprises. It is the perspective view which represented typically the structure of the scintillator panel which the inspection apparatus of the large sized structure of this invention comprises.

Hereinafter, a specific configuration of the inspection apparatus for a large structure according to the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 is a cross-sectional view schematically showing the configuration of a radiation detector provided in the inspection apparatus for a large structure according to the present invention. The radiation detector 1 includes a scintillator panel 2, an output substrate 3, and a power supply unit 11. The scintillator panel 2 has a phosphor layer 6. The phosphor layer 6 absorbs the energy of incident X-rays and absorbs electromagnetic waves having a wavelength in the range of 300 to 800 nm, that is, from ultraviolet light centering on visible light. It emits scintillation light that is electromagnetic waves (light) in the range of infrared light.

The scintillator panel 2 includes a substrate 4, a partition wall 5 formed thereon, that is, a partition wall 5 for forming a cell, a phosphor layer 6 filled in a space partitioned by the partition wall 5, and a surface of the partition wall 5. It is composed of a shielding layer 12 formed between the phosphor layer 6 and a reflection layer 13.

The output substrate 3 has a photoelectric conversion layer 8 and an output layer 9 on a substrate 10 in which pixels composed of photoelectric conversion elements and TFTs are two-dimensionally formed. The radiation detector 1 is obtained by bonding or adhering the light-emitting surface of the scintillator panel 2 and the photoelectric conversion layer 8 of the output substrate 3 via the diaphragm layer 7 made of polyimide resin or the like. When the light emitted from the phosphor layer 6 reaches the photoelectric conversion layer 8, photoelectric conversion is performed in the photoelectric conversion layer 8, and an electric signal is output through the output layer 9. In the scintillator panel provided in the inspection apparatus for a large structure according to the present invention, each cell is partitioned by a partition wall. Therefore, the pixel size and pitch of the photoelectric conversion elements arranged in a grid pattern, and the cell size of the scintillator panel By matching the length and the pitch, each pixel of the photoelectric conversion element can be associated with each cell of the scintillator panel.

The scintillator panel provided in the inspection apparatus for a large structure according to the present invention comprises a substrate, a partition placed on the substrate, and a phosphor layer filled in a cell partitioned by the partition. It is characterized by.

“Substrate” refers to a plate-like support on which a partition wall is placed. Examples of the material of the substrate include polymers, semiconductors, metals, ceramics, and glass. Examples of the polymer compound include polyester, cellulose acetate, polyamide, polyimide, polycarbonate, or carbon fiber reinforced resin. Examples of the semiconductor include silicon, germanium, gallium arsenide, gallium phosphide, and gallium nitrogen. Examples of the metal include aluminum, iron, copper, lead, tungsten, and molybdenum. Examples of the ceramic include aluminum oxide, aluminum nitride, mullite, and steatite. Examples of the glass include quartz, borosilicate glass, and chemically tempered glass.

When high-energy X-rays are irradiated, most of the X-rays are scattered in the large structure, and when this is directly applied to the scintillator panel, the obtained transmission image, that is, the sharpness of the image is deteriorated. For this reason, the substrate selectively absorbs scattered low-energy X-rays (hereinafter referred to as “scattered X-rays”) and selectively does not scatter high-energy X-rays (hereinafter referred to as “straight-forward X-rays”). Those that permeate through are preferred. More specifically, a substrate having an X-ray absorption characteristic equivalent to that of lead having a thickness of 5 to 20 mm is preferable.

The scintillator panel provided in the inspection apparatus for large structures of the present invention has a partition wall. Scattering of scintillation light is suppressed by the partition walls, and scattered X-rays can be absorbed, so that the sharpness of the obtained image is improved.

FIG. 2 is a cross-sectional view schematically showing the configuration of the scintillator panel provided in the inspection apparatus for large structures according to the present invention.

The height L1 of the partition wall 5 is preferably 0.4 to 50 mm, more preferably 1 to 20 mm. When L1 exceeds 50 mm, straight X-rays are scattered in the phosphor layer, and the sharpness of the obtained image may be reduced. On the other hand, if L1 is less than 0.4 mm, high-energy straight X-rays cannot be sufficiently converted to scintillation light, and the brightness of the scintillator panel may decrease.

The interval L2 between adjacent partition walls is preferably 0.1 to 5 mm, more preferably 0.2 to 1 mm. If L2 is less than 0.1 mm, it is difficult to form a phosphor layer in the cell. On the other hand, if L2 exceeds 5 mm, the sharpness of the obtained image may be reduced.

The bottom width L3 of the partition wall is preferably 0.01 to 0.3 mm, more preferably 0.03 to 0.15 mm. If L3 is less than 0.01 mm, pattern defects are likely to occur. On the other hand, when L3 exceeds 0.3 mm, the volume of the phosphor layer becomes insufficient, and the brightness of the scintillator panel may decrease.

The top width L4 of the partition walls is preferably 0.005 to 0.2 mm, and more preferably 0.02 to 0.1 mm. When L4 is less than 0.005 mm, the strength of the partition walls is reduced, and pattern defects are likely to occur. On the other hand, if L4 exceeds 0.2 mm, the area from which the scintillation light can be extracted from the phosphor layer becomes narrow, and the brightness of the scintillator panel may decrease.

For L1 to L4, the cross section of the scintillator panel perpendicular to the substrate is exposed by a polishing device such as a cross section polisher, and the cross section is observed with a scanning electron microscope (for example, S2400; manufactured by Hitachi, Ltd.) and measured. Can do. Here, the width of the partition wall at the contact portion between the partition wall and the substrate is L3. The width of the topmost part of the partition is L4.

In addition to its strength, the partition walls are preferably made of an inorganic material in order to increase the X-ray absorption rate and the light reflection rate. Here, the inorganic substance means a simple part of a carbon compound (a carbon allotrope such as graphite or diamond) and a compound composed of an element other than carbon. The term “consisting of inorganic substances” does not exclude the existence of components other than inorganic substances in a strict sense, but is not limited to impurities contained in the raw material inorganic substances themselves or impurities mixed in the process of manufacturing the partition walls. The presence of components other than is permissible. As an inorganic substance used as the raw material for the partition wall, for example, a metal such as aluminum, iron, copper, lead, tungsten, or molybdenum, a metal oxide such as titanium oxide or aluminum oxide, or a glass such as borosilicate glass can be given.

The porosity of the partition walls is preferably 25% or less. If the porosity exceeds 25%, the strength of the partition wall may be insufficient. The porosity of the partition wall is obtained by taking a cross-sectional image of the partition wall perpendicular to the substrate with a scanning electron microscope, distinguishing the solid part and the cavity part of the partition wall by binarization, and analyzing the ratio of the cavity part by image analysis. Can be measured.

In the scintillator panel provided in the inspection apparatus for large structures according to the present invention, the reflectance of the substrate constituting the scintillator panel and the partition wall placed on the substrate is preferably 25 to 85%. Here, the substrate and the partition placed on the substrate are those in which only the partition is placed on the substrate, and the cells partitioned by the partition are not filled with the phosphor layer. Say. In addition, when a reflective layer or a shielding layer, which will be described later, is formed on the surface of the substrate and the partition wall before being filled with the phosphor layer, it means a state including them. The reflectance refers to the SCI reflectance at a wavelength of 530 nm measured using a spectrocolorimeter (for example, CM-2600d; manufactured by Konica Minolta Co., Ltd.). The reflectance of the substrate and the partition placed on the substrate is The reflectance refers to the reflectance when light is applied to the substrate and the partition from the side on which the partition is placed. If the reflectance is less than 25%, the brightness of the scintillator panel may be lowered. On the other hand, if the reflectance exceeds 85%, the sharpness of the image may be lowered. This reduction in the sharpness of the image is considered to be caused by a decrease in the absorption of scintillation light by the substrate and the partition walls and an increase in the rate at which scintillation light by scattered X-rays reaches the photoelectric conversion layer. That is, since scattered X-rays have low energy, scintillation light is likely to be emitted only on the side close to the substrate in the phosphor layer. Here, when the reflectance of the substrate and the partition wall placed on the substrate exceeds 85%, light emitted by scattered X-rays in the vicinity of the substrate is efficiently extracted to the photoelectric conversion layer side. Sharpness may be reduced. On the other hand, when the reflectance is 85% or less, light emitted by scattered X-rays is moderately absorbed by the partition in the process of traveling a long distance from the substrate side to the photoelectric conversion layer side, whereas high energy Since the straight X-rays radiate scintillation light almost uniformly in any part from the substrate side to the photoelectric conversion layer side of the phosphor layer, the influence of absorption by the barrier ribs is smaller than that of the scattered X-rays. For this reason, it is considered that the influence of scattered X-rays is relatively reduced and the sharpness of the image is improved.

It is preferable that the scintillator panel provided in the inspection apparatus for a large structure of the present invention has a reflective layer containing a metal oxide between the partition wall and the phosphor layer. Here, having a reflective layer between the barrier rib and the phosphor layer refers to, for example, a state in which the reflective layer is formed on the surface of the substrate and the barrier rib in contact with the phosphor layer. The reflective layer preferably contains a metal oxide as a main component. In addition, that a metal oxide is a main component means that the ratio of the metal oxide in the reflective layer is 50% by volume or more. When the scintillator panel has a reflective layer containing a metal oxide between the barrier ribs and the phosphor layer, the reflectance of the substrate and the barrier ribs placed on the substrate can be controlled appropriately. .

The average thickness of the reflective layer is preferably 5 to 50 μm. Here, the average thickness of the reflective layer is a value obtained by dividing the area of the reflective layer of 10 cells randomly selected in the cross section of the scintillator panel perpendicular to the substrate by the formation length of the reflective layer. The formation length of the reflection layer refers to the total extension of the length of the portion where the reflection layer and the lower layer (such as a partition wall or a shielding layer) are in contact with each other in the cross section of the 10 cells. More specifically, the average thickness of the reflective layer is calculated by exposing the cross section of the scintillator panel perpendicular to the substrate with a polishing apparatus, observing the cross section with a scanning electron microscope, and performing image processing. Can do.

If the average thickness of the reflective layer is less than 5 μm, the reflectivity may be insufficient. On the other hand, when the thickness exceeds 50 μm, the reflectance becomes too high, and the sharpness of the obtained image may be lowered. Moreover, since the volume of the phosphor layer becomes insufficient, the brightness of the scintillator panel may be lowered.

The metal oxide contained in the reflective layer is preferably a compound selected from the group consisting of titanium oxide, zirconium oxide, aluminum oxide, barium oxide, bismuth oxide and gadolinium oxide in order to achieve a more suitable reflectance. A reflective layer composed of these oxides is preferable because it has an appropriate reflectance. In order to further improve the sharpness of the image by absorbing scattered X-rays generated in the phosphor layer, the heavy elements barium oxide, bismuth oxide and gadolinium oxide are more preferable.

When the scintillator panel provided in the inspection apparatus for a large structure according to the present invention has a reflective layer, the average thickness of the reflective layer in the upper half of the cell is larger than the average thickness of the reflective layer in the lower half of the cell. Is preferred. Here, the average thickness of the reflective layer in the upper half of the cell means the area of the upper half of the cell, that is, the height of the partition, for 10 cells randomly selected in the cross section of the scintillator panel perpendicular to the substrate. This is a value obtained by dividing the area of the reflective layer formed in the region above the median value of the length L1 (the bisection point of the partition wall height L1) by the formation length of the reflective layer. Similarly, the average thickness of the reflective layer in the lower half of the cell is the area of the lower half of the cell, i.e. the partition wall, for 10 randomly selected cells in the cross section of the scintillator panel perpendicular to the substrate. A value obtained by dividing the area of the reflective layer formed in the region below the median value of the height L1 (the bisector of the partition wall height L1) by the formation length of the reflective layer. By adopting such a configuration, scintillation light due to scattered X-rays generated at the cell bottom is easily absorbed by the partition walls, and the sharpness of the image is easily improved.

It is preferable that the scintillator panel provided in the inspection apparatus for a large structure of the present invention has a shielding layer containing metal between the partition wall and the phosphor layer. Since the scintillator panel has a shielding layer containing metal between the partition walls and the phosphor layer, leakage of scintillation light to adjacent cells can be suppressed. Further, when the shielding layer is an X-ray absorption layer having an appropriate X-ray absorption, scattered X-rays generated when high energy straight X-rays interact with the phosphor layer in the cell are absorbed. Thus, since leakage to adjacent cells can be suppressed, it is possible to suppress a reduction in the sharpness of the obtained image. The shielding layer is preferably composed mainly of metal. In addition, that metal is a main component means that the proportion of metal in the shielding layer is 50% by volume or more.

Examples of the shielding layer forming method include a vacuum film-forming method such as a vacuum deposition method, a sputtering method, or a CVD method, a plating method, a paste coating method, or a spraying method by spraying. Examples of the metal contained in the shielding layer include aluminum, chromium, silver, tungsten, molybdenum, and lead. Silver, tungsten, molybdenum, and lead having high X-ray absorption are preferable. The average thickness of the shielding layer is preferably 0.0001 to 0.5 mm. When the average thickness of the shielding layer is less than 0.0001 mm, the effect of suppressing scintillation light leakage and the X-ray absorption effect tend to be insufficient. On the other hand, if the thickness exceeds 0.5 mm, the phosphor layer volume becomes insufficient, and the brightness of the scintillator panel may be lowered. The average thickness of the shielding layer can be calculated by the same method as the average thickness of the reflective layer.

When both the shielding layer and the reflecting layer are formed between the barrier rib and the phosphor layer, the reflecting layer is formed on the shielding layer in order to avoid insufficient reflectance due to absorption by the shielding layer. It is preferable.

In the scintillator panel provided in the inspection apparatus for large structures of the present invention, the phosphor layer is filled in the cells partitioned by the partition walls. Examples of the phosphor contained in the phosphor layer include CsI, CsBr, BaF ₂ , BaFI, BaFBr, GOS (Gd ₂ O ₂ S), GSO (Gd ₂ SiO ₅ ), BGO (BiGe ₃ O ₁₂ ), and LSO. (Lu ₂ SiO ₅ ), LuAP (LuAlO ₃ ), PbWO ₄ or CaWO ₄ may be mentioned. In order to increase the luminous efficiency, an activator may be added to the phosphor. Examples of the activator added to the phosphor include indium (In), thallium (Tl), lithium (Li), potassium (K), rubidium (Rb), sodium (Na), terbium (Tb), and europium (Eu). ) Or praseodymium (Pr).

In the scintillator panel provided in the inspection apparatus for large structures according to the present invention, it is preferable that the phosphor layer contains a granular phosphor, and the average primary particle diameter of the phosphor is 1 to 50 μm. When the phosphor layer contains a granular phosphor, it is possible to control the scintillation light scattering in the phosphor layer to a suitable one, and the barrier ribs are obtained by appropriately absorbing scintillation light due to scattered X-rays. The sharpness of the image is improved.

The phosphor layer contains a granular phosphor. In the cross section of the scintillator panel perpendicular to the substrate, all the phosphors filled in 10 cells randomly selected have a major axis and a short axis. The average value of the values obtained by measuring the diameter and dividing the major axis by the minor axis is 10 or less. In addition, the average primary particle diameter of the phosphor is the circular equivalent particle of the cross-sectional area of all the granular phosphors filled in 10 cells selected at random in the cross section of the scintillator panel perpendicular to the substrate. It is a weighted average value obtained by calculating diameters and weighting them by area ratio. More specifically, the average primary particle diameter of the phosphor is calculated by exposing a cross section of the scintillator panel perpendicular to the substrate with a polishing apparatus, observing the cross section with a scanning electron microscope, and performing image processing. be able to.

Moreover, in order to control the scattering of the scintillation light in the phosphor layer containing the granular phosphor to be more suitable, it is preferable to fill the space between the phosphor particles with a high refractive index resin. Examples of the granular phosphor include GOS (Gd ₂ O ₂ S) doped with thallium (Tl).

In the scintillator panel of the present invention, it is preferable that the phosphor layers filled in the cells partitioned by the partition walls have a plurality of modes having different compositions and / or thicknesses. By setting it as such a structure, the scintillator panel which a fluorescent substance layer consists of a fluorescent substance layer of the several aspect from which X-ray absorptivity differs is obtained. Here, the X-ray absorption rate refers to the absorption rate of each phosphor layer for 1 MeV X-ray, and is calculated using EGS5, which is a radiation simulation program, based on the composition and thickness of each phosphor layer. Can do.

As a method of forming a phosphor layer having a plurality of modes with different compositions and / or thicknesses, for example, fluorescence is emitted only to a specific cell through a patterned metal mask in a cell partitioned by a partition wall. The method of repeating the method of vacuum-printing a body paste using several types of fluorescent substance paste is mentioned.

The scintillator panel provided in the inspection apparatus for large structures of the present invention is used for inspection of large structures and exhibits high sensitivity and sharpness of images with respect to high energy X-rays. The internal structure of an object can be inspected with high accuracy while being non-destructive. Here, the large structure is ordinary 18-8-20-N which is a ready-mixed concrete whose minimum width is 20 cm or more and whose X-ray transmittance with energy of 500 keV is defined by JIS A5308. Of the cured product is smaller than the transmittance at a site of 20 cm in thickness.

The inspection apparatus for a large structure of the present invention is a radiation detector that irradiates a large structure with X-rays from an X-ray source having an acceleration voltage of 500 kV to 30 MV, and an X-ray transmitted through the large structure. A detection function. In other words, the inspection apparatus for a large structure according to the present invention irradiates the large structure with an X-ray from an X-ray source having an acceleration voltage of 500 kV to 30 MV, and an X-ray transmitted through the large structure. It is for implement | achieving the inspection method of a large sized structure provided with the detection process detected with a radiation detector.

The acceleration voltage of the X-ray source is preferably 1 MV or more, and more preferably 2 MV or more, in order to increase the generation efficiency of high energy X-rays. Moreover, in order to raise the detection efficiency in a detector, 20 MV or less is preferable and 10 MV or less is more preferable.

The irradiation process and the detection process included in the inspection method may be started / finished at the same time, or their timing may be mixed. More specifically, for example, the detection process is started by irradiating a weak structure with weak X-rays in advance, and the irradiation process is started after the acceleration voltage of the X-ray source is set to 500 kV to 30 MV after a certain time. Alternatively, a large structure may be irradiated with X-rays from an X-ray source having an acceleration voltage of 500 kV to 30 MV in advance, and the detection process may be started after a certain time.

Examples of the method for forming the partition include machining, photolithography, or formation by a 3D printer. Since a high-strength partition can be formed with high definition, the partition is formed by photolithography or 3D printer using a photosensitive paste. Is preferably formed. Among them, it is preferable to form a partition mainly composed of glass by photolithography using a photosensitive glass paste because processing of a large area is easy, tact time is short, and manufacturing cost is low.

The partition wall mainly composed of glass is obtained by, for example, applying a photosensitive paste containing glass powder to the surface of a base material to obtain a coating film, exposing and developing the coating film, and baking the partition wall. It can be formed by a pattern forming step of obtaining a previous pattern and a firing step of firing the pattern to obtain a partition pattern. In order to produce a partition mainly composed of glass, 50 to 100% by mass of the inorganic component contained in the glass powder-containing paste used in the coating step needs to be glass powder.

The glass powder contained in the glass powder-containing paste is preferably glass that softens at the firing temperature, and more preferably low-softening point glass having a softening temperature of 700 ° C. or lower.

The softening temperature is determined by calculating the endothermic end temperature at the endothermic peak from the DTA curve obtained by measuring the sample using a differential thermal analyzer (eg, differential type differential thermal balance TG8120; manufactured by Rigaku Corporation) by the tangent method. It can be obtained by inserting. More specifically, first, using a differential thermal analyzer, using alumina powder as a standard sample, the temperature is raised from room temperature at 20 ° C./min to measure the inorganic powder serving as a measurement sample to obtain a DTA curve. Then, from the obtained DTA curve, the softening point Ts obtained by extrapolating the endothermic end temperature at the endothermic peak by the tangent method can be used as the softening temperature.

In order to obtain a low softening point glass, a metal oxide selected from the group consisting of lead oxide, bismuth oxide, zinc oxide and alkali metal oxides, which is an effective compound for lowering the softening point of glass, is used. However, it is preferable to adjust the softening temperature of the glass using an alkali metal oxide. Here, the alkali metal refers to a metal selected from the group consisting of lithium, sodium and potassium.

The proportion of the alkali metal oxide in the low softening point glass is preferably 2 to 20% by mass. When the proportion of the alkali metal oxide is less than 2% by mass, the softening temperature becomes high, and it becomes necessary to perform the firing step at a high temperature, and defects are likely to occur in the partition walls. On the other hand, when the ratio of the alkali metal oxide exceeds 20% by mass, the viscosity of the glass is excessively lowered in the firing step, and the shape of the obtained grid-like post-firing pattern tends to be distorted.

The low softening point glass preferably contains 3 to 10% by mass of zinc oxide in order to optimize the viscosity at high temperature. When the proportion of zinc oxide in the low softening point glass is less than 3% by mass, the viscosity at high temperature increases. On the other hand, when the content of zinc oxide exceeds 10% by mass, the production cost of the low softening point glass increases.

Further, the low softening point glass is a metal selected from the group consisting of oxides of silicon oxide, boron oxide, aluminum oxide and alkaline earth metal for the purpose of adjusting stability, crystallinity, transparency, refractive index or thermal expansion characteristics. It is preferable to contain an oxide. Here, the alkaline earth metal refers to a metal selected from the group consisting of magnesium, calcium, barium and strontium. An example of the composition range of a preferred low softening point glass is shown below.
Alkali metal oxide: 2 to 20% by mass
Zinc oxide: 3-10% by mass
Silicon oxide: 20-40% by mass
Boron oxide: 25-40% by mass
Aluminum oxide: 10-30% by mass
Alkaline earth metal oxide: 5 to 15% by mass
The particle diameter of the inorganic powder containing glass powder can be measured using a particle size distribution measuring device (for example, MT3300; manufactured by Nikkiso Co., Ltd.). More specifically, the measurement can be performed after the inorganic powder is introduced into the sample chamber of the particle size distribution measuring apparatus filled with water and subjected to ultrasonic treatment for 300 seconds.

The 50% volume average particle diameter (hereinafter referred to as “D50”) of the low softening point glass powder is preferably 1.0 to 4.0 μm. When D50 is less than 1.0 μm, the glass powder is aggregated, and uniform dispersibility cannot be obtained, and the flow stability of the paste is lowered. On the other hand, when D50 exceeds 4.0 μm, the surface unevenness of the post-baking pattern obtained in the baking process becomes large, and this tends to cause the partition wall to be destroyed later.

In order to control the shrinkage rate of the lattice pattern in the baking process and to maintain the shape of the partition wall finally obtained, the glass powder-containing paste is not only a low softening point glass but also a high softening point glass having a softening temperature exceeding 700 ° C. Ceramic particles such as silicon oxide, aluminum oxide, titanium oxide or zirconium oxide may be contained as a filler. The proportion of the filler in the entire inorganic component is preferably 50% by mass or less in order to prevent the strength of the partition walls from being reduced due to inhibition of the sintering of the glass powder. The filler D50 is preferably the same as that of the low softening point glass powder.

The coating step is a step of applying a glass powder-containing paste to the entire surface or a part of the surface of the substrate to obtain a coating film. As the substrate, a highly heat-resistant support such as a glass plate or a ceramic plate can be used. Examples of the method for applying the glass powder-containing paste include a screen printing method, a bar coater, a roll coater, a die coater, and a blade coater. The thickness of the resulting coating film can be adjusted by the number of coatings, the screen mesh size, the viscosity of the paste, or the like.

In the pattern formation process, for example, the coating film obtained in the coating process is exposed through a photomask having a predetermined opening, and a portion soluble in the developer in the coating film after exposure is dissolved. And a developing step to be removed.

The exposure process is a process in which a necessary part of the coating film is photocured by exposure or an unnecessary part of the coating film is photodecomposed to make any part of the coating film soluble in the developer. . The development step is a step of obtaining a lattice-shaped pre-baking pattern in which only a necessary portion remains by dissolving and removing a portion soluble in the developer in the coating film after exposure with the developer.

In the exposure process, an arbitrary pattern may be directly drawn with a laser beam or the like without using a photomask. An example of the exposure apparatus is a proximity exposure machine. Examples of the actinic rays irradiated in the exposure step include near infrared rays, visible rays, and ultraviolet rays, and ultraviolet rays are preferable. Examples of the light source include a low pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a halogen lamp, and a germicidal lamp, and an ultra high pressure mercury lamp is preferable. Although exposure conditions vary depending on the thickness of the coating film, exposure is usually carried out for 0.01 to 30 minutes using an ultrahigh pressure mercury lamp with an output of 1 to 100 mW / cm ² .

Examples of the development method in the development process include an immersion method, a spray method, and a brush method. As the developer, a solvent capable of dissolving unnecessary portions in the coating film after exposure may be appropriately selected, but an aqueous solution containing water as a main component is preferable. For example, when the glass powder-containing paste contains a polymer having a carboxyl group, an alkaline aqueous solution can be selected as the developer. Examples of the alkaline aqueous solution include an inorganic alkaline aqueous solution such as sodium hydroxide, sodium carbonate or calcium hydroxide, or an organic alkaline aqueous solution such as tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, monoethanolamine or diethanolamine. An organic alkali aqueous solution is preferable because it can be easily removed in the firing step. The concentration of the alkaline aqueous solution is preferably 0.05 to 5% by mass, and more preferably 0.1 to 1% by mass. If the alkali concentration is less than 0.05% by mass, unnecessary portions in the coated film after exposure may not be sufficiently removed. On the other hand, when the alkali concentration exceeds 5% by mass, there is a risk of peeling or corrosion of the lattice-shaped pattern before firing. The development temperature is preferably 20 to 50 ° C. to facilitate process control.

In order to perform pattern formation by exposure and development, the glass powder-containing paste applied in the coating process needs to be photosensitive. That is, the glass powder-containing paste needs to contain a photosensitive organic component. The proportion of the organic component in the photosensitive glass powder-containing paste is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass. When the organic component is less than 30% by mass, the dispersibility of the inorganic component in the paste is lowered, and not only is the defect easily generated in the baking process, but the paste viscosity is increased and the applicability is lowered. Stability is also likely to decrease. On the other hand, when the organic component exceeds 80% by mass, the shrinkage rate of the lattice pattern in the baking process is increased and defects are easily generated.

The glass powder contained in the photosensitive glass powder-containing paste preferably has a softening temperature of 480 ° C. or higher in order to remove organic components almost completely in the firing step and ensure the strength of the partition wall finally obtained. . When the softening temperature is less than 480 ° C., the glass powder is softened before the organic components are sufficiently removed in the firing step, and the organic components remain in the glass after sintering, which induces coloring of the partition walls. There is a concern that the brightness of the scintillator panel is lowered.

In the photosensitive glass powder-containing paste, in order to suppress light scattering during exposure and form a highly accurate pattern, the refractive index n1 of the glass powder and the refractive index n2 of the organic component are -0.1 < It is preferable that the relationship of n1-n2 <0.1 is satisfied, more preferably the relationship of -0.01 ≦ n1-n2 ≦ 0.01, and the relationship of −0.005 ≦ n1-n2 ≦ 0.005. It is further preferable to satisfy In addition, the refractive index of glass powder can be suitably adjusted with the composition of the metal oxide which glass powder contains.

The refractive index of glass powder can be measured by the Becke line detection method. Moreover, the refractive index of an organic component can be calculated | required by measuring the coating film which consists of an organic component by ellipsometry. More specifically, the refractive index (ng) of the glass powder or organic component at a wavelength of 436 nm (g line) at 25 ° C. can be set to n1 or n2, respectively.

Examples of the photosensitive organic component contained in the photosensitive glass powder-containing paste include a photosensitive monomer, a photosensitive oligomer, and a photosensitive polymer. Here, the photosensitive monomer, photosensitive oligomer or photosensitive polymer refers to a monomer, oligomer or polymer whose chemical structure is changed by a reaction such as photocrosslinking or photopolymerization upon irradiation with actinic rays.

As the photosensitive monomer, a compound having an active carbon-carbon unsaturated double bond is preferable. Examples of such a compound include a compound having a vinyl group, an acryloyl group, a methacryloyl group, or an acrylamide group. However, in order to increase the density of photocrosslinking and form a highly accurate pattern, Functional methacrylate compounds are preferred.

The photosensitive oligomer or photosensitive polymer is preferably an oligomer or polymer having an active carbon-carbon unsaturated double bond and a carboxyl group. Such oligomers or polymers include, for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid or their anhydrides, carboxyl group-containing monomers, methacrylic acid esters, acrylic acid esters , Styrene, acrylonitrile, vinyl acetate or 2-hydroxyacrylate. Examples of a method for introducing an active carbon-carbon unsaturated double bond into an oligomer or polymer include acrylic acid chloride, methacrylic acid chloride, or a mercapto group, amino group, hydroxyl group or carboxyl group of the oligomer or polymer. Examples thereof include a method of reacting an allylic chloride, an ethylenically unsaturated compound having a glycidyl group or an isocyanate group, or a carboxylic acid such as maleic acid.

By using a photosensitive monomer or photosensitive oligomer having a urethane bond, it is possible to obtain a glass powder-containing paste that can relieve stress in the initial stage of the baking process and that is less likely to cause pattern defects in the baking process.

The photosensitive glass powder-containing paste may contain a photopolymerization initiator as necessary. Here, the photopolymerization initiator refers to a compound that generates radicals upon irradiation with actinic rays. Examples of the photopolymerization initiator include benzophenone, methyl o-benzoylbenzoate, 4,4-bis (dimethylamino) benzophenone, 4,4-bis (diethylamino) benzophenone, 4,4-dichlorobenzophenone, 4-benzoyl- 4-methyldiphenyl ketone, dibenzyl ketone, fluorenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone , Diethylthioxanthone, benzyl, benzylmethoxyethyl acetal, benzoin, benzoin methyl ether, benzoin butyl ether, anthraquinone, 2-t-butylanthraquinone, anthrone, benza Throne, dibenzosuberone, methyleneanthrone, 4-azidobenzalacetophenone, 2,6-bis (p-azidobenzylidene) cyclohexanone, 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone, 1-phenyl- 1,2-Butadione-2- (O-methoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) oxime, 1,3-diphenylpropanetrione-2- (O— Ethoxycarbonyl) oxime, 1-phenyl-3-ethoxypropanetrione-2- (O-benzoyl) oxime, Michler's ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, -Benzyl-2-dimethylamino-1- (4-morpholinofe E) Photoreductive dyes such as butanone-1, naphthalenesulfonyl chloride, quinolinesulfonyl chloride, N-phenylthioacridone, benzthiazole disulfide, triphenylformine, benzoin peroxide, eosin or methylene blue and ascorbic acid or triethanol A combination of a reducing agent with an amine or the like can be mentioned.

When the photosensitive glass powder-containing paste contains a polymer having a carboxyl group as the photosensitive polymer, the solubility in an alkaline aqueous solution during development is improved. The acid value of the polymer having a carboxyl group is preferably 50 to 150 mgKOH / g. When the acid value is 150 mgKOH / g or less, the development margin becomes wide. On the other hand, when the acid value is 50 mgKOH / g or more, the solubility in an alkaline aqueous solution is not lowered, and a high-definition pattern can be obtained.

The photosensitive glass powder-containing paste can be obtained by preparing various components so as to have a predetermined composition and then uniformly mixing and dispersing them with a three-roller or a kneader.

The viscosity of the photosensitive glass powder-containing paste can be appropriately adjusted depending on the addition ratio of inorganic powder, thickener, organic solvent, polymerization inhibitor, plasticizer, anti-settling agent, etc., but the range is 2 to 200 Pa. -S is preferable. For example, when a photosensitive glass powder-containing paste is applied to a substrate by a spin coating method, a viscosity of 2 to 5 Pa · s is preferable, and when applied to a substrate by a blade coater method or a die coater method, A viscosity of 10 to 50 Pa · s is preferred. When a photosensitive glass powder-containing paste is applied by a single screen printing method to obtain a coating film having a thickness of 10 to 20 μm, a viscosity of 50 to 200 Pa · s is preferable.

In the firing step, the lattice-shaped pre-fired pattern obtained in the pattern forming step is fired to decompose and remove the organic components contained in the glass powder-containing paste, and the glass powder is softened and sintered, thereby firing the lattice. This is a step of obtaining a post pattern, that is, a partition wall. The firing conditions vary depending on the composition of the glass powder-containing paste and the type of substrate, but can be fired in a firing furnace in an air, nitrogen or hydrogen atmosphere, for example. Examples of the firing furnace include a batch-type firing furnace or a belt-type continuous firing furnace. The firing temperature is preferably 500 to 1000 ° C., more preferably 500 to 800 ° C., and further preferably 500 to 700 ° C. When the firing temperature is lower than 500 ° C., the organic components are not sufficiently decomposed and removed. On the other hand, if the firing temperature exceeds 1000 ° C., the base material that can be used is limited to a high heat-resistant ceramic plate or the like. The firing time is preferably 10 to 60 minutes.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Raw material for glass powder-containing paste)
The raw materials used for the production of the photosensitive glass powder-containing paste are as follows.
Photosensitive monomer M-1: Trimethylolpropane triacrylate photosensitive monomer M-2: Tetrapropylene glycol dimethacrylate photosensitive polymer: Copolymer having a mass ratio of methacrylic acid / methyl methacrylate / styrene = 40/40/30 Of 0.4 equivalent of glycidyl methacrylate with respect to the carboxyl group (weight average molecular weight 43000; acid value 100)
Photopolymerization initiator: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (IC369; manufactured by BASF)
Polymerization inhibitor: 1,6-hexanediol-bis [(3,5-di-tert-butyl-4-hydroxyphenyl) propionate])
Ultraviolet absorber solution: Sudan IV (manufactured by Tokyo Ohka Kogyo Co., Ltd.) γ-butyrolactone 0.3% by mass solution viscosity modifier: Flownon EC121 (manufactured by Kyoeisha Chemical Co., Ltd.)
Solvent: γ-butyrolactone low softening point glass powder:
SiO ₂ 27% by mass, B ₂ O ₃ 31% by mass, ZnO 6% by mass, Li ₂ O 7% by mass, MgO 2% by mass, CaO 2% by mass, BaO 2% by mass, Al ₂ O ₃ 23% by mass, refraction. Rate (ng) 1.56, glass softening temperature 588 ° C., thermal expansion coefficient 70 × 10 ⁻⁷ (K ⁻¹ ), average particle diameter 2.3 μm
High softening point glass powder:
SiO ₂ 30% by mass, B ₂ O ₃ 31% by mass, ZnO 6% by mass, MgO 2% by mass, CaO 2% by mass, BaO 2% by mass, Al ₂ O ₃ 27% by mass, refractive index (ng) 1.55 , Softening temperature 790 ° C., thermal expansion coefficient 32 × 10 ⁻⁷ (K ⁻¹ ), average particle diameter 2.3 μm
(Preparation of paste containing glass powder)
4 parts by weight of photosensitive monomer M-1, 6 parts by weight of photosensitive monomer M-2, 24 parts by weight of photosensitive polymer, 6 parts by weight of photopolymerization initiator, 0.2 part by weight of polymerization inhibitor, and 12 parts 8 parts by mass of the UV absorber solution was dissolved in 38 parts by mass of solvent at a temperature of 80 ° C. After cooling the obtained solution, 9 parts by mass of a viscosity modifier was added to obtain an organic solution 1. The refractive index (ng) of the organic coating film obtained by applying and drying the obtained organic solution 1 on a glass plate was 1.555.

After adding 40 parts by mass of the low softening point glass powder and 10 parts by mass of the high softening point glass powder to 50 parts by mass of the organic solution 1, the mixture was kneaded with a three-roller kneader to obtain a glass powder-containing paste. .

(Raw material for phosphor paste)
Phosphor 1: terbium-doped gadolinium oxysulfide phosphor with an average particle diameter of 10 μm 2: terbium-doped gadolinium oxysulfide phosphor with an average particle diameter of 2 μm 3: terbium-doped oxysulfide with an average particle diameter of 5 μm Gadolinium phosphor 4: Terbium-doped gadolinium oxysulfide binder having an average particle diameter of 30 μm: 7 cp etosel (registered trademark) (generic name: ethyl cellulose; manufactured by Nissei Seisaku)
Solvent: Terpineol (Preparation of phosphor paste)
85 parts by mass of

phosphor

1, 3 parts by mass of binder and 12 parts by mass of solvent were stirred to obtain phosphor paste 1.

Further, 85 parts by mass of

phosphor

2, 3 parts by mass of binder and 12 parts by mass of solvent were stirred to obtain phosphor paste 2.

Further, 85 parts by mass of

phosphor

3, 3 parts by mass of binder and 12 parts by mass of solvent were stirred to obtain phosphor paste 3.

In addition, 85 parts by mass of

phosphor

4, 3 parts by mass of binder and 12 parts by mass of solvent were stirred to obtain phosphor paste 4.

Further, 10 parts by mass of

phosphor

1, 3 parts by mass of binder and 87 parts by mass of solvent were stirred to obtain phosphor paste 5.

Further, 42 parts by mass of

phosphor

1, 3 parts by mass of binder and 55 parts by mass of solvent were stirred to obtain phosphor paste 6.

(Raw material for reflective layer paste)
Metal oxide 1: Titanium oxide metal oxide having an average particle diameter of 0.25 μm 2: Zirconium oxide metal oxide having an average particle diameter of 0.3 μm 3: Aluminum oxide metal oxide having an average particle diameter of 0.2 μm 4: Average particle diameter 0.5 μm barium oxide metal oxide 5: Gadolinium oxide metal oxide having an average particle size of 0.5 μm 6: Bismuth oxide metal oxide having an average particle size of 0.3 μm 7: Lead oxide metal oxide having an average particle size of 0.25 μm Product 8: Cobalt oxide binder having an average particle size of 0.2 μm: 100 cp etosel (registered trademark) (generic name: ethyl cellulose; manufactured by Nisshinsei)
Solvent: Terpineol (Preparation of reflective layer paste)
A reflective layer paste 1 was obtained by adding 9 parts by mass of the metal oxide 1 to an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C.

Further, 9 parts by mass of metal oxide 2 was added and kneaded in an organic solution obtained by heating and dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. to obtain a reflective layer paste 2.

Further, 9 parts by mass of metal oxide 3 was added and kneaded in an organic solution obtained by dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. to obtain a reflective layer paste 3.

Further, 9 parts by mass of metal oxide 4 was added and kneaded in an organic solution in which 1 part by mass of a binder was dissolved in 90 parts by mass of an organic solvent by heating at 80 ° C. to obtain a reflective layer paste 4.

Further, 9 parts by mass of metal oxide 5 was added and kneaded in an organic solution obtained by dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. to obtain a reflective layer paste 5.

Further, 9 parts by mass of metal oxide 6 was added and kneaded in an organic solution obtained by dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. to obtain a reflective layer paste 6.

Further, 9 parts by mass of the metal oxide 7 was added to and kneaded with 1 part by mass of a binder in an organic solution obtained by heating and dissolving in 90 parts by mass of an organic solvent at 80 ° C. to obtain a reflective layer paste 7.

Further, 9 parts by mass of metal oxide 8 was added and kneaded in an organic solution obtained by dissolving 1 part by mass of a binder in 90 parts by mass of an organic solvent at 80 ° C. to obtain a reflective layer paste 8.

Further, 0.1 parts by mass of a binder is added to 99 parts by mass of an organic solvent heated and dissolved at 80 ° C. at 80 ° C., and 0.9 parts by mass of metal oxide 1 is added and kneaded. Obtained.

Further, 2.7 parts by mass of metal oxide 1 was added and kneaded in an organic solution obtained by dissolving 0.3 parts by mass of a binder in 97 parts by mass of an organic solvent at 80 ° C. Obtained.

Further, 18 parts by mass of metal oxide 1 was added and kneaded in an organic solution obtained by heating and dissolving 2 parts by mass of a binder in 80 parts by mass of an organic solvent at 80 ° C. to obtain a reflective layer paste 11.

In addition, 27 parts by mass of metal oxide 1 was added and kneaded in an organic solution obtained by dissolving 3 parts by mass of a binder in 70 parts by mass of an organic solvent at 80 ° C. to obtain a reflective layer paste 12.

Further, 45 parts by mass of metal oxide 1 was added to and kneaded in an organic solution obtained by dissolving 5 parts by mass of a binder in 50 parts by mass of an organic solvent at 80 ° C. to obtain a reflective layer paste 13.

(Formation of partition walls)
As a substrate, a soda glass plate of 125 mm × 125 mm × 0.7 mm was used. The glass powder-containing paste was applied to the surface of the substrate with a die coater so that the thickness after drying was a desired thickness, and dried to obtain a coating film of the glass powder-containing paste. Next, the coating film of the glass powder-containing paste was exposed using an ultrahigh pressure mercury lamp through a photomask having openings corresponding to a desired pattern. The exposed coating film was developed in a 0.5% by mass ethanolamine aqueous solution, and the unexposed portion was removed to obtain a lattice-shaped pre-baking pattern. The obtained lattice-shaped pre-fired pattern was fired in air at 585 ° C. for 15 minutes to form lattice-shaped partition walls mainly composed of glass.

(Evaluation of reflectance)
Using a spectrocolorimeter (CM-2600d; manufactured by Konica Minolta), SCI reflectance at a wavelength of 530 nm was measured.

(Evaluation of brightness and sharpness)
Using a radiation detector with a scintillator panel and an output board bonded together, X-ray transmission inspection is performed for a 30 cm thick reinforced concrete when X-rays are irradiated for a certain period of time. The sharpness was evaluated from the clarity of the reinforcing bars in the captured image. Both brightness and sharpness were evaluated by visual five-step evaluation, the best case was determined as A, and B, C, D, and E were determined in order of goodness. When the sharpness is E, it is highly likely that the radiation detector constituting the large-structure inspection apparatus of the present invention is not suitable.

(Example 1)
In the partition wall forming operation, the glass powder-containing paste was applied so that the thickness after drying was 1.5 mm. For the exposure, a chromium mask having a grid-like opening with a pitch of 0.5 mm and an opening width of 0.03 mm was used. The porosity of the obtained partition wall is 2.5%, the partition wall height L1 is 1 mm, the partition wall distance L2 is 0.5 mm, the partition wall bottom width L3 is 0.05 mm, and the partition wall top width L4 is 0.03 mm. there were. Moreover, the reflectance of the base material in which the obtained partition was formed was 15%.

The base material on which the grid-like partition walls were formed was set in a vacuum printer, and the phosphor paste 1 was printed to fully fill the cells with the phosphor paste. Then, it dried at 150 degreeC for 60 minutes, and the scintillator panel 1 was obtained. The average primary particle diameter of the phosphor calculated by exposing the cross section of the scintillator panel perpendicular to the substrate with a polishing apparatus, observing the cross section with a scanning electron microscope, and performing image processing was 10 μm.

The obtained scintillator panel 1 was bonded to an output substrate having a resolution of 0.5 mm pitch so that the cells and the pixels correspond to each other on a one-to-one basis, whereby the radiation detector 1 was obtained. When the brightness and sharpness of the radiation detector 1 were evaluated using an X-ray source having an acceleration voltage of 1 MV, the brightness was C and the sharpness was C, both of which were good.

(Example 2)
A base material on which partition walls were formed in the same manner as in Example 1 was produced. The base material was set in a vacuum printing machine, the reflective layer paste 9 was printed, and the cell was fully filled with the reflective layer paste. Thereafter, it was dried at 90 ° C. for 60 minutes to form a reflective layer on the surfaces of the substrate and the partition walls. The average thickness of the reflective layer was 2 μm, and the reflectance of the substrate after forming the reflective layer was 20%. Thereafter, the phosphor paste was filled in the same manner as in Example 1 to obtain the scintillator panel 2, and after alignment with the output substrate, bonding was performed to obtain the radiation detector 2. The brightness of the radiation detector 2 was C, and the sharpness was C, both of which were good.

(Example 3)
A radiation detector 3 was obtained in the same manner as in Example 2 except that the reflective layer paste 10 was used as the reflective layer paste. The average thickness of the reflective layer was 5 μm, the reflectance of the substrate after forming the reflective layer was 25%, the luminance of the radiation detector 3 was C, and the sharpness was B, both of which were good.

Example 4
A radiation detector 4 was obtained in the same manner as in Example 2 except that the reflective layer paste 1 was used as the reflective layer paste. The average thickness of the reflective layer was 20 μm, the reflectivity of the substrate after forming the reflective layer was 60%, the luminance of the radiation detector 4 was B, and the sharpness was B, both of which were good.

(Example 5)
A radiation detector 5 was obtained in the same manner as in Example 2 except that the reflective layer paste 12 was used as the reflective layer paste. The average thickness of the reflective layer was 50 μm, the reflectivity of the substrate after forming the reflective layer was 85%, the luminance of the radiation detector 5 was B, and the sharpness was C, both of which were good.

(Example 6)
A radiation detector 5 was obtained in the same manner as in Example 2 except that the reflective layer paste 13 was used as the reflective layer paste. The average thickness of the reflective layer was 80 μm, the reflectance of the substrate after forming the reflective layer was 90%, and the luminance of the radiation detector 5 was C, which was good. The sharpness was D, which was relatively good.

(Example 7)
A scintillator panel 7 was obtained in the same manner as in Example 4 except that in the formation of the partition walls, a chrome mask having a grid-like opening with a pitch of 0.2 mm and an opening width of 0.02 mm was used for exposure. The porosity of the obtained partition wall was 2%, the partition wall height L1 was 1 mm, the partition wall distance L2 was 0.2 mm, the partition wall bottom width L3 was 0.04 mm, and the partition wall top width L4 was 0.02 mm. . The average thickness of the reflective layer was 20 μm, and the reflectance of the substrate after forming the reflective layer was 40%.

The obtained scintillator panel 7 was bonded to an output substrate having a resolution of 0.2 mm pitch so that the cells and the pixels correspond to each other on a one-to-one basis, whereby the radiation detector 7 was obtained. The brightness of the radiation detector 7 was C and the sharpness was A, both of which were good.

(Example 8)
A scintillator panel 8 was obtained in the same manner as in Example 4 except that in the formation of the partition walls, a chrome mask having a grid-like opening having a pitch of 1 mm and an opening width of 0.04 mm was used for exposure. The partition wall obtained had a porosity of 3%, partition wall height L1 of 1 mm, partition wall spacing L2 of 1 mm, partition wall bottom width L3 of 0.08 mm, and partition wall top width L4 of 0.04 mm. The average thickness of the reflective layer was 20 μm, and the reflectance of the substrate after forming the reflective layer was 70%.

The obtained scintillator panel 8 was bonded to an output substrate having a resolution of 1 mm pitch so that the cells and the pixels correspond to each other on a one-to-one basis, whereby the radiation detector 8 was obtained. The brightness of the radiation detector 8 was A and the sharpness was C, both of which were good.

Example 9
In the same manner as in Example 4, a shielding layer was formed by sputtering aluminum on a substrate on which lattice-like partition walls were formed. The average thickness of the shielding layer was 1 μm. Thereafter, in the same manner as in Example 4, a reflection layer was formed, filled with a phosphor paste, and bonded to an output substrate to obtain a radiation detector 9. The average thickness of the reflective layer was 20 μm, the reflectance of the substrate on which the barrier ribs were formed was 45%, the luminance of the radiation detector 9 was C, and the sharpness was A, both of which were good.

(Example 10)
A radiation detector 10 was obtained in the same manner as in Example 9 except that the reflective layer paste 11 was used as the reflective layer paste. The average thickness of the reflective layer was 30 μm, the reflectivity of the substrate after forming the reflective layer was 55%, the brightness of the radiation detector 10 was B, and the sharpness was A, both of which were good.

(Example 11)
A radiation detector 11 was obtained in the same manner as in Example 9 except that the reflective layer paste 12 was used as the reflective layer paste. The average thickness of the reflective layer was 50 μm, the reflectivity of the substrate after forming the reflective layer was 65%, the luminance of the radiation detector 11 was C, and the sharpness was B, both of which were good.

Example 12
A radiation detector 12 was obtained in the same manner as in Example 9 except that the reflective layer paste 13 was used as the reflective layer paste. The average thickness of the reflective layer was 80 μm, the reflectivity of the substrate after forming the reflective layer was 65%, the luminance of the radiation detector 12 was C, and the sharpness was C, both of which were good.

(Example 13)
To an organic solution obtained by dissolving 2 parts by mass of a binder (100 cP etcel) in 60 parts by mass of an organic solvent (terpineol) at 80 ° C., 38 parts by mass of tungsten powder (particle size: 1 μm) was added and kneaded. A line absorbing layer paste was obtained. The base material on which grid-like partition walls were formed in the same manner as in Example 4 was set in a vacuum printer, the X-ray absorbing layer paste was printed, and the cells were fully filled with the X-ray absorbing layer paste. Then, it dried at 90 degreeC for 60 minutes, and formed the X-ray absorption layer on the surface of a board | substrate and a partition. The average thickness of the X-ray absorption layer was 10 μm. Thereafter, as in Example 4, a reflective layer was formed, filled with a phosphor paste, and bonded to an output substrate to obtain a radiation detector 12. The average thickness of the reflective layer was 20 μm, the reflectance of the substrate after the reflective layer was formed was 40%, the luminance of the radiation detector 13 was C, and the sharpness was A, both of which were good.

(Example 14)
A radiation detector 14 was obtained in the same manner as in Example 2 except that the reflective layer paste 2 was used as the reflective layer paste. The average thickness of the reflective layer was 20 μm, the reflectance of the substrate after forming the reflective layer was 55%, the brightness of the radiation detector 14 was B, and the sharpness was B, both of which were good.

(Example 15)
A radiation detector 15 was obtained in the same manner as in Example 2 except that the reflective layer paste 3 was used as the reflective layer paste. The average thickness of the reflective layer was 25 μm, the reflectivity of the substrate after the reflective layer was formed was 40%, the luminance of the radiation detector 15 was C, and the sharpness was B, both of which were good.

(Example 16)
A radiation detector 16 was obtained in the same manner as in Example 2 except that the reflective layer paste 4 was used as the reflective layer paste. The average thickness of the reflective layer was 20 μm, the reflectivity of the substrate after forming the reflective layer was 45%, the luminance of the radiation detector 16 was B, and the sharpness was B, both of which were good.

(Example 17)
A radiation detector 17 was obtained in the same manner as in Example 2 except that the reflective layer paste 5 was used as the reflective layer paste. The average thickness of the reflective layer was 15 μm, the reflectance of the substrate after forming the reflective layer was 55%, the luminance of the radiation detector 17 was B, and the sharpness was A, both of which were good.

(Example 18)
A radiation detector 18 was obtained in the same manner as in Example 2 except that the reflective layer paste 6 was used as the reflective layer paste. The average thickness of the reflective layer was 15 μm, the reflectance of the substrate after the reflective layer was formed was 30%, the luminance of the radiation detector 18 was C, and the sharpness was B. Both were good.

(Example 19)
A radiation detector 19 was obtained in the same manner as in Example 2 except that the reflective layer paste 7 was used as the reflective layer paste. The average thickness of the reflective layer was 15 μm, the reflectance of the substrate after forming the reflective layer was 20%, and the luminance of the radiation detector 19 was D, which was relatively good. The sharpness was B, which was good.

(Example 20)
A radiation detector 20 was obtained in the same manner as in Example 2 except that the reflective layer paste 8 was used as the reflective layer paste. The average thickness of the reflective layer was 20 μm, the reflectance of the substrate after forming the reflective layer was 5%, and the brightness of the radiation detector 20 was E, but the sharpness was B, which was good.

(Example 21)
A radiation detector 21 was obtained in the same manner as in Example 9 except that the phosphor paste 2 was used as the phosphor paste. The average primary particle diameter of the phosphor was 2 μm. The average thickness of the reflective layer was 20 μm, the reflectance of the substrate after forming the reflective layer was 45%, and the luminance of the radiation detector 21 was D, which was relatively good. The sharpness was A, which was good.

(Example 22)
A radiation detector 22 was obtained in the same manner as in Example 9 except that the phosphor paste 3 was used as the phosphor paste. The average primary particle diameter of the phosphor was 5 μm. The average thickness of the reflective layer was 20 μm, the reflectance of the substrate after the reflective layer was formed was 45%, the luminance of the radiation detector 22 was C, and the sharpness was A, both of which were good.

(Example 23)
A radiation detector 23 was obtained in the same manner as in Example 9 except that the phosphor paste 4 was used as the phosphor paste. The average primary particle diameter of the phosphor was 30 μm. The average thickness of the reflective layer was 20 μm, the reflectance of the substrate after forming the reflective layer was 45%, the luminance of the radiation detector 23 was B, and the sharpness was A, both of which were good.

(Example 24)
As a phosphor, a sintered body ingot of terbium-doped gadolinium oxysulfide is machined into a columnar rectangular parallelepiped of 0.9 × 0.3 × 0.3 mm, and inserted into each cell one by one to form a phosphor layer. Except for the formation, a radiation detector 24 was obtained in the same manner as in Example 9. The average thickness of the reflective layer was 20 μm, the reflectance of the substrate after forming the reflective layer was 45%, the luminance of the radiation detector 24 was C, and the sharpness was C, both of which were good.

(Example 25)
In the formation of the partition walls, a radiation detector 25 was obtained in the same manner as in Example 4 except that the glass powder-containing paste was applied so that the thickness after drying was 3 mm. The partition wall porosity was 2.5%, the partition wall height L1 was 2 mm, the partition wall spacing L2 was 0.5 mm, the partition wall bottom width L3 was 0.07 mm, and the partition wall top width L4 was 0.03 mm. there were. The average thickness of the reflective layer was 20 μm, the reflectance of the substrate after the reflective layer was formed was 45%, the luminance of the radiation detector 25 was A, and the sharpness was B, both of which were good.

(Example 26)
A radiation detector 26 was obtained in the same manner as in Example 4 except that the partition wall was formed by applying the glass powder-containing paste so that the thickness after drying was 1 mm. The porosity of the obtained partition wall is 2%, the partition wall height L1 is 0.5 mm, the partition wall distance L2 is 0.5 mm, the partition wall bottom width L3 is 0.04 mm, and the partition wall top width L4 is 0.03 mm. there were. The average thickness of the reflective layer was 20 μm, the reflectivity of the substrate after forming the reflective layer was 70%, the luminance of the radiation detector 26 was C, and the sharpness was B, both of which were good.

(Example 27)
A radiation detector 27 was obtained in the same manner as in Example 4 except that the partition wall was formed by applying the glass powder-containing paste so that the thickness after drying was 0.4 mm. The obtained partition wall has a porosity of 1.5%, the partition wall height L1 is 0.2 mm, the partition wall interval L2 is 0.5 mm, the partition wall bottom width L3 is 0.03 mm, and the partition wall top width L4 is 0.00 mm. It was 03 mm. The average thickness of the reflective layer is 25 μm, the reflectance of the substrate after the reflective layer is formed is 75%, the luminance of the radiation detector 27 is D, and the sharpness is D. Since the partition is low, both the luminance and the sharpness are high. Although slightly lower, both were relatively good.

(Example 28)
The radiation detector 4 was evaluated using an X-ray source having an acceleration voltage of 0.5 MV in the evaluation of luminance and sharpness. The brightness was D and the sharpness was B, both of which were good.

(Example 29)
In the formation of the phosphor layer, as in Example 2, the substrate on which the grid-like partition walls and the reflective layer were formed was set in a vacuum printing machine, on which 0.2 mm square openings had a pitch of 0.5 mm. After arranging the metal mask arranged in a checkered pattern and performing alignment so that the opening of the metal mask and the opening of the cell partitioned by the partition wall are aligned, the phosphor paste 5 is printed, The target cell was fully filled with the phosphor paste 5. Next, after shifting the metal mask by 0.5 mm and performing alignment in the same manner, the phosphor paste 1 was printed and the target cell was fully filled with the phosphor paste 1. Then, it dried at 150 degreeC for 60 minutes, and obtained the scintillator panel 29 of the aspect similar to the schematic diagram of FIG. 4 from which the aspect of a fluorescent substance layer differs between the mutually adjacent cells. The ratio, P / Q, of the X-ray absorption rate P of the cell filled with the phosphor paste 1 to the X-ray absorption rate Q of the cell filled with the phosphor paste 5 was 10.

The radiation detector 29 was obtained by bonding the scintillator panel 29 after alignment to an output substrate having a resolution of 0.5 mm pitch. Using the radiation detector 29, an X-ray transmission test was performed when X-rays from an X-ray source with an acceleration voltage of 1 MV were applied to 30 cm thick reinforced concrete. An operation for obtaining only the intensity of high-energy X-rays, that is, straight X-rays, that is, an operation for subtracting the signal of the cell filled with the phosphor paste 1 after multiplying the signal of the cell filled with the phosphor paste 5 by an appropriate coefficient. In addition, for the cell filled with the phosphor paste 5, a transmission image complemented by the average value of the signals of the four cells in the upper, lower, left and right directions was constructed. As a result, the brightness was C and the sharpness was B. It was.

(Example 30)
In Example 29, a metal mask in which 0.2 mm square openings were arranged in a grid pattern with a pitch of 2 mm was used as a metal mask used for printing the phosphor paste 5 in forming the phosphor layer. The phosphor paste 1 was aligned and filled using a metal mask designed to be printed only on cells other than the cells filled with the phosphor paste 5. Then, it dried at 150 degreeC for 60 minutes, and obtained the scintillator panel 30 of the aspect similar to the schematic diagram of FIG. 5 from which the aspect of a fluorescent substance layer differs between the mutually adjacent cells. The ratio, P / Q, of the X-ray absorption rate P of the cell filled with the phosphor paste 1 to the X-ray absorption rate Q of the cell filled with the phosphor paste 5 was 10.

Thereafter, evaluation was performed in the same manner as in Example 29. The luminance was C and the sharpness was A, both of which were good.

(Example 31)
In Example 30, evaluation was performed in the same manner except that the phosphor paste 6 was used instead of the phosphor paste 5. The ratio of the X-ray absorption rate P of the cell filled with the phosphor paste 1 to the X-ray absorption rate Q of the cell filled with the phosphor paste 6, P / Q was 2. The brightness was C and the sharpness was B, both of which were good.

(Example 32)
A radiation detector 32 was obtained in the same manner as in Example 5 except that the drying temperature after printing of the reflective layer paste 12 was set to 160 ° C. The average thickness of the reflective layer is 50 μm, the reflectivity of the substrate after forming the reflective layer is 85%, the brightness of the radiation detector 32 is B, and the sharpness is B. The sharpness is improved compared to the radiation detector 5. .

When the thickness of the reflection layer of the scintillator panel constituting the radiation detector 5 and the radiation detector 32 was analyzed in detail, the average thickness of the reflection layer in the upper half of the cell in the radiation detector 5 was 45 μm. The average thickness of the reflective layer in the lower half was 55 μm, and the average thickness of the reflective layer in the upper half of the cell was smaller than the average thickness of the reflective layer in the lower half of the cell, whereas radiation detection In the vessel 32, the average thickness of the reflective layer in the upper half of the cell is 60 μm, the average thickness of the reflective layer in the lower half of the cell is 40 μm, and the average thickness of the reflective layer in the upper half of the cell is It was larger than the average thickness of the reflective layer in the lower half of the cell.

(Example 33)
A radiation detector 33 was obtained in the same manner as in Example 12 except that the drying temperature after printing of the reflective layer paste 13 was set to 160 ° C. The average thickness of the reflective layer is 80 μm, the reflectance of the substrate after the reflective layer is formed is 75%, the brightness of the radiation detector 33 is C, and the sharpness is B. The sharpness is improved compared to the radiation detector 12. .

When the thickness of the reflection layer of the scintillator panel constituting the radiation detector 12 and the radiation detector 33 was analyzed in detail, in the radiation detector 12, the average thickness of the reflection layer in the upper half of the cell was 75 μm. The average thickness of the reflective layer in the lower half was 85 μm, and the average thickness of the reflective layer in the upper half of the cell was smaller than the average thickness of the reflective layer in the lower half of the cell, whereas radiation detection In the vessel 32, the average thickness of the reflective layer in the upper half of the cell is 90 μm, the average thickness of the reflective layer in the lower half of the cell is 75 μm, and the average thickness of the reflective layer in the upper half of the cell is It was larger than the average thickness of the reflective layer in the lower half of the cell.

(Comparative Example 1)
As a substrate, a soda glass plate of 125 mm × 125 mm × 0.7 mm was used. The phosphor paste 1 was applied to the surface of the base material with a die coater so that the thickness after drying was 1.5 mm, and dried to obtain a scintillator panel 2. The obtained scintillator panel 2 was bonded to an output substrate having a resolution of 0.25 mm to obtain a radiation detector 31. Using the radiation detector 31, an X-ray transmission test was performed when X-rays from an X-ray source with an acceleration voltage of 1 MV were applied to 30 cm thick reinforced concrete. The brightness of the obtained image was A, the sharpness was E, and the sharpness was very low.

(Comparative Example 2)
In Comparative Example 1, evaluation was performed in the same manner as in Comparative Example 1 except that the phosphor layer was applied and dried so that the thickness after drying was 1 mm. The brightness of the obtained image was A, the sharpness was E, and the sharpness was very low.

(Comparative Example 3)
In Comparative Example 1, the evaluation was performed in the same manner as in Comparative Example 1 except that the phosphor layer was applied and dried so that the thickness after drying was 0.2 mm. The brightness of the obtained image was D, the sharpness was E, and the sharpness was very low.

(Comparative Example 4)
The radiation detector 31 was evaluated using an X-ray source having an acceleration voltage of 0.5 MV in the evaluation of luminance and sharpness. The luminance of the obtained image was C, the sharpness was E, and the sharpness was very low.

(Comparative Example 5)
The radiation detector 4 was evaluated using an X-ray source having an acceleration voltage of 0.2 MV in the evaluation of luminance and sharpness, but no image was obtained. This is considered to be because the X-ray permeability was too low and X-rays did not pass through the concrete.

From the above results, it is clear that the inspection apparatus for large structures of the present invention contributes to a marked improvement in image sharpness in nondestructive inspection.

DESCRIPTION OF SYMBOLS 1 Radiation detector 2 Scintillator panel 3 Output board | substrate 4 Board | substrate 5 Partition 6 Phosphor layer 7 Diaphragm layer 8 Photoelectric conversion layer 9 Output layer 10 Board | substrate 11 Power supply part 12 Shielding layer 13 Reflective layer

The present invention is useful for nondestructive inspection of large structures.

Claims

An irradiation function for irradiating a large structure with X-rays from an X-ray source with an acceleration voltage of 500 kV to 30 MV
An inspection apparatus for a large structure comprising a detection function for detecting X-rays transmitted through the large structure with a radiation detector, wherein the radiation detector is placed on the substrate. And a scintillator panel comprising a phosphor layer filled in a cell partitioned by the partition, and a large structure inspection apparatus.
2. The inspection apparatus for a large structure according to claim 1, wherein the reflectance of the substrate and the partition wall placed on the substrate is 25 to 85%.
3. The inspection apparatus for a large structure according to claim 1, wherein the scintillator panel includes a reflective layer between the partition wall and the phosphor layer, and the reflective layer contains a metal oxide.
The large-structure inspection device according to claim 3, wherein an average thickness of the reflective layer is 5 to 50 µm.
5. The inspection apparatus for a large structure according to claim 3, wherein the metal oxide is a compound selected from the group consisting of titanium oxide, zirconium oxide, aluminum oxide, barium oxide, bismuth oxide and gadolinium oxide.
The inspection of the large structure according to any one of claims 3 to 5, wherein an average thickness of the reflective layer in the upper half of the cell is larger than an average thickness of the reflective layer in the lower half of the cell. apparatus.
The inspection apparatus for a large structure according to any one of claims 1 to 6, wherein the phosphor layer contains a granular phosphor, and an average primary particle diameter of the phosphor is 1 to 50 µm.
The large structure inspection according to any one of claims 1 to 7, wherein the scintillator panel includes a shielding layer between the partition wall and the phosphor layer, and the shielding layer contains a metal. apparatus.
The large structure inspection apparatus according to any one of claims 1 to 8, wherein a height of the partition wall is 0.4 to 50 mm.
The inspection apparatus for a large structure according to any one of claims 1 to 9, wherein the phosphor layer has a plurality of modes having different compositions and / or thicknesses.
The X-ray absorption rate in the phosphor layer having the maximum X-ray absorption rate is P,
When the X-ray absorption rate in the phosphor layer having the minimum X-ray absorption rate is Q,
The inspection apparatus for a large structure according to any one of claims 1 to 10, which satisfies a relationship of P / Q≥1.5.